Boiler and the like



Feb. 11, 1930. T.E. MURRAY BOILER ND THE LIKE Filed June 1, 1923 2Sheets-Sheet 1 Murray 7770mm; E. 0 gg Xki/ylum Feb. 11, 1930. T. E.MURRAY 1,746,711

BOILER AND THE LIKE Filed June 1, 1925 2 Sheets-Sheet 2 E Mar/"17y Z 8%homas Q). NU-Mm Patented Feb. 11, 1930 UNITED STATES PATENT, OFFHUE"THOMAS E. MURRAY, OF NEW YORK,'1\T. Y.; JOSEPH BRADLEY MURRAY, THOMAS E.MURRAY, J'R., AND JOHN F. MURRAY EXECUTORS OF SAID THOMAS E. MURRAY,

DECEASED BOILER AND THE LIKE Application filed June 1, 1923. Serial Noi642,725.

The invention relates in general to heaters for various fluids and 1sdeslgned particularly for heating water or superheating steam inboilers. In a previous application No.

642,427 I have described a boiler construction including tubes withplates or other heat conducting elements between them. The presentapplication is based specifically on certain improvements over thestructure of the above application. It includes also certain separatefeatures of novelty.

The invention is illustrated in the accompanying drawings in which Fig.1 is a. perspective view with portions sectioned off showing anembodiment of the invention;

Fig. 2 is a horizontal section through the combustion chamber of theboiler of Fig. 1;

Fig. 3 is a detail showing means for sup.- plying fuel and air to thecombustion chamber of the boiler;

Figs. 4 and 5 are details of modified arrangements for' supplying fueland air to the boiler;

Fig. 6 is a fragmentary viewillustrating the construction of tubularwall members and closure members secured thereto;

Fig. 7 shows an alternative construction which may beused in place ofthat shown in Fig. 6; i

Fig. 8 is a fragmentary vertical section through onewall of the boiler.

Referring. in detail tothe drawings, the boiler includes front and rearheaders 10 and 12 of usual construction connected by boiler tubes 14 anda steam dome 16 connected by nipples 18 to the headers 10 and by pipes20 to the headers 12. The headers 10 are supported on a tubular member22 extending transversely for the full width of the boiler, andsimilarly the headers 12 are supported by a tubular member 24-. The reartransverse member 24 is supported bv a hollow cross-member 27 formingpart'of the rear wall 26 of the boiler, this wall being made up of aplurality of tubular members 28 spaced apart from one another as shownin Fig. 2.

Each member 28 has a closure member secured thereto which'comprises anoutwardly extending longitudinal plate 30 and a plate RElSSUED 32 weldedor otherwise secured to the outer surface of the member 28." As showninFig. 6, the plates 30 of the adjacent members overlap one another andeffectively close the space between the adjacent members. Theseoverlapping plates are not rigidly attached to one another, but aremerely loosely held in engagement with one another so as to permitexpansion and contraction of the wall.

The tubular members 28 are secured at their lower ends to a hollowbox-like member 34 forming-in effect a lower sill for supporting thewall 26. The tubular members 28 may be shouldered as at 36, Fig. 8, soas to form a seat onf'the member 34 and the jointmay be welded orotherwise made steam-tight. In some cases the ends of the members 28will be rolled over as at 38 and when this means of forming the joint isemployed, the member 34 will be formed with openings opposite themembers 28 to permit the insertion of a rolling tool. Plugs 40 will beemployed to close such openings. v

. The rear wall 26, including the cross mem-i bers 27 and 34 form ahollow or cellular steam-tight structure which is adapted to serve as asuperheater. The wet steam 'from outlet pipe 19 is connected to thelower hollow sill member 34 to convey the superheated steam to thedesired point.

The side walls 42 and 44 and the front wall 46 are-also .each composedof a mul tiplicity of tubular members 28 spaced apart as shown in Fig.2, and the spaces between such members are closed by fin or platemembers 30 as shown in Fig. 6, and described in connection with the rearwall 26. These members are connected at their lower ends with hollowsill members 48 and 50 at the sides and with a sill52 at the front end.

The front wall 46 which is carried by the member 52' supports at itsupper end a hollow cross member 54. Rearwardly extending members 56 and58 are connected with the tubular cross member 54 by suitable nipplesand at the drum 16 passes through the pipe 17 to the their rear endsthese members 56 and 58 are similarly connected with the member 22.

The members 56 and 58 are conneteed by hollow members 28 similar inconstruction to those above referred to, and provided with similar finportions 30 so'as to form a top wall or roof 60 over the forward portionof the boiler forming in effect what in this art is known as a Dutchoven.

The sill members 34, 48, 50 and 52 as above described are of hollowconstruction and as shown in Fig. 8 are in open communication with thetubular members 28 so that in effect they form headers. The members 24,54, 56 and 58 are similarly connected and also form headers connectingwith the tubular members 28. This arrangement providesa construction inwhich steam can be circulated through the back wall to be superheated asabove described and Water can be circulated through the side and frontwalls of the boiler and also through the roof 60 of the Dutch ovenportion. Feed water is supplied to the boiler through one or more pipesconnected to any of the sill members, for example as by means of pipes62 shown in Fig. 1, entering the sides of the sill members 48 and 52.

The comparatively cool water enteringthe pipe or pipes'62 is circulatedthrough the sill members and throughthe tubular members 28 of theseveral walls. The sill members 48, 50 and 52 may each be connected witha separate water supply or they may be connected by pipe connections,not shown, so as to permit of a circulation between the separatesections. The side walls 42 and 44 of the boiler' may extend up to the,full height of the tubes 20 so as to enclose the entire bank of watertubes and the top of the boiler may be closed in any suitable manner andsuitable fiues leading to the stack may be provided. These arrangementsare not shown in the drawings as the of the present invention andvarious known arrangements can be adopted without departing from theinvention.

At the corners where the walls 42 and 44 meet the end walls 26 and 46,the space between the adjacent tubular sections 28 is closed byoverlapping plates 30 similar to the members 30 which close the spacesbetween the various members of the walls. The walls 42, 44, 26 and 46enclose a chamber 64 within which combustion of fuel takes place ashereinafter described.

Surrounding the inner walls which are made up of the members 28, is anouter structure composed of side walls 66 and 68, front and rear endwalls 70 and 72; .These walls are separated from the. hollow wallsa'short distance so as to form a surrounding air space 74. Openings 7 6are provided in the outer wall to permit air to enter the air space andmeans are provided for introducing air from this space into thecombustion chamber. A

specific design forms no part 4 shown in Fig. 3, a conical sleeve 78 islocated between two of the members 28 and forms a passage-way throughwhich air can flow from the air space 74 to the combustion chamber'64 asshown by the arrows. A fuel pipe 80 passes through the wall 70 andextends axially through the sleeve 78. Suitable fuel such as oil, gas orpulverized coal is delivered by hand or stoker, and this fuel mixes withthe air flowing from the space 74 through the sleeve 78 and combustiontakes place inside of the chamber 64. There may be several of theseburners according to requirements and in Fig.- 2 six burners areillustrated. Instead of passing the fuel pipe throughthe sleeve 78through which the air passes, this pipe may pass directly through theplates 30 between adjacent members 28 as shown in Fig. 4 and the air tosupport combustion may pass through separate conduits 82 as shown.

In Fig. 5, I have shown a slightly modified arrangement wherein the fuelpipe 80 is provided with openings 84 through which the air from the airspace 74 is drawn as the fuel is forced into the combustion chamber.

Instead of closing the space between the adjacent tubular members 28, bymeans of flanged members 30; 32 above described, I

may use a formed plate as shown in Fig. 7

having an arcuate portion 33 and outwardly extendingfins or plates 35and 37. These fins will contact with and overlap similar fins onadjacent tubular members 28 as will be understood.

From the foregoing it will be perceived that the multiplicity. oftubular members 28 provide means whereby the water or steam may becirculated through the walls of the boiler. These members are connectedat top through the pipe 80 or coal may be introduced 1 and bottom bybox-like members as, for example, 24 and 34, Fig. 8, which serve asheaders and also as supporting members. The hollow members 24 and 22 areconnected by suitable nipples with the boiler headers 10 and 12 as willbe understood. Circulating the feed water through the walls enables meto use metallic walls instead of brickwork or masonry walls heretoforeused for stationary boilers, and this water, of course, absorbs heatwhich would be lost in constructions where brick walls or the like wereused. The walls, therefore in effect form a superheater for the steam, awater, and also help' to preheat the combustion air.

The members which close the spaces between the tubular members 28 serveto prevent the escape of combustion gases from between the tubularmembers and also to conduct heat to the tubular members and the watercirculating therein.

The outer walls which surround the hollow walls as described provide anair space for preheating the air used to support combus' lit) preheaterfor the boiler feed tion. The use of such preheated air raises theefliciency ofthe boiler and utilizes heat which would ordinarily be lostby radiation to the surrounding atmosphere in boilers made ac cording tothe usual practice prior to my invention.

The hollow wall construction herein de scribed can also be used for thefloor of the boiler as indicated at 28 in Fig. 2. This is advantageouswhen liquid or powdered fuel is used as it permits the circulation ofwater through the floor bottom and prevents the adhesion of slagthereto.

may be employed. The same is true of the tight joint. The closure issuflicient to perdesign shown in Fig.7,with the flanges 35 and 37 formedby opposite portions of a common plate 33. And the opposite flanges ofsuch units may be in the same plane as indicated in Figs. 6 and 7, orthey may be set at 'an angle to each other as in the corner plates orflanges 30. These separate units are not claimed herein,'being claimedin separate applications which I have filed Nos. 715,369 and 720,734.

. Such units are separately formed and then assembled, the overlappingflanges being free to move with relation to each other so as toaccommodate the distortion or unequal ex pansion which occurs under theheat of the furnace. Being unconnected, the units are readily assembled.Also they are capable of separate replacement in case of injury to anyone of them. Although they are preferably in contact as shown, theydonot make a gasmit the circulation of air for preheating it asdescribed. But such an air space between the inner and the outer wallsis useful in insulat' ing the latter from excessive heating even'withoutany circulation of air between them.

' The solid heat-conducting plates between the tubes are preferablywelded to the sides of the latter at points between the rear and frontof the tubes and, lying in this intermediate space, are well in front ofthe outer wall, no matter how closely this may be brought up to thebacks of the tubes, The use of two'such plates bridging each space hasan advantage.

in providing a short path for the conduction 'of heat from the plates tothe respective tubes.

It is also an'advantage to use sheet metal or rolled steel shapes asindicated and to weld them to the tubes. 60-

Such rolled steel has a toughness and durability which particularlyadaptsit for the use in question, and by welding them to drawn steeltubing a unit is produced whichis particularly well fitted tovthe It isa matter of great advantage that the plates between the tubes 'areexposed directly to the radiant heat of the burning fuel in thecombustion chamber, so that the inner sides of the tubes and theintermediate plates present a wide exposure to such radiant heat inproportion to the quantity of water flowing through the tubes. Theheating effect obtained in this way is very much greater than that whichis obtained by circulation of the hot gases out of direct line'with theburningfuel. The boiler of this invention is particularly adapted forgenerating high pressure steam and for utilizing the extremely hightemperatures in the combustion chamber which can be obtained with thenozzle type of burnersdescribed, projecting powdered coal or liquid orgaseous fuel into the combustion chamber. The highest temperaturesobtainable in this way cannot be'used in ordinary boilers with masonrywalls forming the combustion chamber and exposed to the radiant heat. Byinterposing on the inner face of the -masonry wall a water wall of'thecharacter described, a boiler of a given size can be run at a rating (ofWater evaporated per hour) very much higher. Or for an industrial plantrequiring a certain quantity of steam, the number of boilers necessarycan be considerably reduced compared with the present standards.

The use of coal dust in connection with the wall of water tubes has aparticular value which has beendemqnstrated in actual installations. Thenatural tendency of water cooled walls is to absorb heat and thus impaircombustion and cause smoking. A refractory surface heated toincandescence has generally been regarded as important in assisting therapid combustion of particles of coal dust. It has been found inpractice that the water wall of this invention, with the watercirculating quickly takes on the appearance of the old type refractorywall heated to incandescence. This is due to a coating of very finelightly adherentash from the jets or flames of coal dust. In the oldfashioned refractory fur nace such ash is deposited in a plastic stateforming a slag. 4

In the water cooledfurnace of this invention the particles on strikingthe wall are immediately cooled below the slaggi'ng temperature (if theywere above thattemperatur'e) and adhere to the surface like a coat ofdust.

' Since the ash does not adhere closely to the metal, the conduction ofheat to the latter is not rapid and the temperature of the ash remainsvconsiderably higher than that of the metal. -The ash builds out fromthemetal and the outer portion attains a temperature h'gh enough toprovide the incandescent surface of refractory material which isimportant in the continuous maintenance of rapid and completecombustlon, -with a minimum of smoke.. The layer of ash finds a limit inrapidly v therethrough thickness which prevents the surface particlesfrom attaining a fusing temperature,

maintaining an approximate balance at which effect can be prolyretarding com- I ried My improved boiler is designed to produce steam ata rate of several hundred per cent of the usual'rating based on areaexposed to the heating .gases and requires for this result a high volumeof intensely hot gas. It becomes important therefore to prevent theexposure of the usual masonry wall to the fire. perience shows that suchwallsare rapidly deteriorated under modern high temperature firing. Themetal fins or extensions of my improved boiler form a shield whichprotects .any outside sheathing.

Such extensions have an additional function to conduct heat to the watertubes so rapidly as to utilize the intense heat of the fire. Ininstallations of this character the distance to which the extensions maybe carbeyond the tubes is-limited. It 'must be so "short that the heatis conducted to the tubes sufliciently rapidly to prevent the outerportions of the extensions from being burned awa or distortedsufficiently to crack them. Suc I conduction of heat to the tube isaffected by the area and the degree of contact of the extension memberwith the tube,

but is chiefly dependent on the distance from the tube to the remotestpart of the extension. Such distances puts a maximum limitation on thedistance between the tubes in the case of high duty boilers (that is,steam generators as distinguished from mere water heaters or the like).

Inpractice, I have found that the maximum distance should not besubstantially greater than the outside diameter of the tubes. Theextensions beyond'the tube, with such spacing, are of less width thanthe diameter of the tubes and can be kept within such liniits as toavoid destruction by the fire.

While I have described quite specifically the details of the boilerillustrated it is'not to be construed that I am limited thereto aschanges in arrangement and substitution of equivalents may be made bythose skilled in the art without departing from the invention as definedin'the appended claims.

What I claim is:

1. In a boiler or the like a wall comprising a multiplicity of pipesarranged in spaced 7 another and each.

relationship alongside one pipe havinga longitudinally extending platesecured thereto which overlaps the plate of the adjacent pipe, saidplates being arranged to substantially or approximately close the to oneanother.

adjacent pipes and to conspace between the the pipes with their atductheatthereto, tached plates being tion to one another.

2. In a boiler or the like, a wall comprising a multiplicity of tubularmembers arranged in a row alongside one another and adapted to have afluid circulated therethrough, and means secured to said tubular members.for substantially or approximately closing the spaces between them andconducting heat to permit relative movement due to expansion andcontraction.

4. A boiler or the like comprising. a number of separately formed unitscom rising'tubular members with longitudinal flanges united thereto,said units being assembled parallel to each other with said flangesoverlapping each other between the tubular members and free to move withrelation to each other.

5. In a boiler or the like, a Wall comprising a multiplicity of verticalpipes communicating with horizontal headers, overlapping members securedto said pipes to close the spaces betwen them and to conduct heat to thefluid in them, the pipes with their attached plates being separate fromone another;

6. A boiler for generating steam at high pressure rapidly comprising afurnace wall exposed on its inner face only to the furnace gases andcomprisinga number of separately formed units consisting of verticallyextending tubular members through which the Water of the boilercirculates with longitudinal flanges united thereto, said units beingassembled parallel to each other with said flanges-substantially orapproximately closing the space between the tubular members,

said units being free to move with relation 7. A boiler adapted forgenerating steam at high pressure having a combustion chamber with awall comprising a multiplicity of upright tubular members spaced apartfrom one another and arranged for water circulation therethrough, metalplates secured to said members and exposed to the radiant heat of theburning fuel and adapted to transmit heat to said tubular members, thetubular members being separately expansible, in combination with burnersof the nozzle type for projecting powdered,'liquid or gaseous fuel intothe combustion chamber.

8. A boiler adapted for generating steam at high pressure having acombustion chamfree to move. with relato the radiant heat of the burningfuel and adapted to transmit heat to thetubular members, in combinationwith burners of the nozzle type for projecting powdered, liquid orgaseous fuel into the combustion chamber.

9. A boiler adapted for generating steam at high pressure having anouter furnace wall and, between the outer wall and the combustionchamber, an inner wall comprising a multiplicity of tubular membersspaced apart from one another and arranged for water circulationtherethrough, metal plates 1 secured to said members and exposed to theradiant heat of the burning fuel and adapted to transmit heat to saidtubular members, the tubular members being separately expansible, incombination with burners of the nozzle type for projecting powdered,liquid or gaseous fuel into the combustion chamber.

10. A boiler adapted for generating steam at high pressure having anouter wall and, between the outer wall and the combustion chamber, aninner wall comprising a multiplicity of separate units composed oftubular members with longitudinal flanges united thereto, said unitsbeing free to move with relation to one another, in combination withburners of the nozzle type for projecting powdered, liquid or gaseousfuel into the combustion chamber. I

11. A boiler having water tubes between 'which the products ofcombustion pass and a. combustion chamber below said tubes and having aforwardly offset portion below the level of such tubes including sidesof water tubes and an arch of water tubes communicating with those atthe sides, both said sides and arch being exposed to the radiant heat ofthe burning fuel and communicating with thecirc'ulating system of theboiler. Y

12. A steam generator including a combustion chamber for-the fuel havinga wall composed of substantially upright tubes connect ed into thecirculation of the generator, said tubes being spaced apart a distancenot substantially greater than their diameter, and

metal extensions from said tubes practically closing the space betweenthem so that only the inner face of such wall is exposed to the directradiant heat of the burning fuel the tubes of said wall being separatefrom and free-to move with relation toone another.

.13. A boiler having inclined, approxi matey horizontal, water tubesbetween whlch 'f the products of combustion pass ands. combustionchamber below said water tubes, with I a. wall of saidchamber comprisinga mul- "tiplicity of upright tubular members spaced apart from oneanother and arranged for water circulation therethrough, and metalextensions secured to said members and exposed to the radiant heat ofthe burning. fuel and adapted to transmit heat to said tubular members,said tubular membersbeing separate from and free to move with relationto one another. 7

14. A boiler having water tubes between which the products of combustionpass and a combustion chamber in advance of said water tubes, with awall of said chamber comprising a multiplicity of tubular. members ar-.

ranged for water circulation therethrough and exposed to the radiantheat of the burning fuel, the boiler having a forwardly oifset portion.belowthe level of the tubes through which the products of combustionpass, said offset portion including anarch above the forward portion ofthe combustion chamber, said arch comprising a water wall exposed to theradiant heat of the burning fuel and communicating with the circulatingsystem of the boiler.

15. A boiler having an overhead bank of tubes through which the furnacegases pass to heat said tubes by convection andhaving, below said bankof tubes, a combustion chamher with an arch of water tubes and. front,back and side walls, all comprising vertically extending water tubesexposed to the direct radiant heatof the burning fuel and presenting acomplete metal face to the furnace.

16. A steam generator including approximately horizontal water tubesheated by convection and a furnace with a combustion chamber below saidtubes and havin a wall composed of substantially upri ht tu es con-,nected into the circulation of t e boiler, said tubes being spaced aparta distance not sub- 'stantially greater than their diameter, and metalextensions from said tubes united thereto with good heat-conductingjoints and practically' closing the space between the tubes ers andhaving acombustion'chamber wall of upright spaced steam generating watertubes with metallic extensions forming a continuous metallic faceexposed to the'direct radiant heat of the burning coal from said burnersand adapted to collect a continuous coating of incandescent ash whichavoidsexcessive cooling of the flame.

18. A steam generator includin in combination approximately horizontaoverhead water tubes heated b convection and a furnace having a comustion chamber below said overhead tubes, all the wall of saidcombustion chamber being composed ofrows of upright tubes connected intothe circulation of the generator and exposed to the heatin gases on theinner sides only of said rows 0 tubes.

In witness whereof, I have hereunto signed my name.

THOMAS E. MURRAY.

